Support rolls cooperating with belts or disposed in an array to support products for transport, processing or pressing, may be required to take up considerable loads.
For those cases in which a bending of the support roll is to be avoided or in which it is important to prevent even very small bendings in relation to the thickness of the transported goods and under the combined effects of pressure, loading and temperature in a transport system or press, various techniques must be employed. Such techniques are particularly important when practically zero support roll bending is permissible if a predetermined geometry of a product is to be maintained.
An obvious way of limiting the bending of a transport and roll is to increase its cross section. This, however, is not always possible, since the outer dimensions of the roll may be limited.
Another approach is to brace the support roll by additional rolls engaging the support roll from the outside. The latter technique cannot be employed in extreme heat environments or other cases in which effective lubrication cannot be ensured.
It is also a common practice to increase the resistance to bending of a support roll to minimize bending in the contact region of the support roll with the conveyor belt, by especially shaping the support roll or the support tube which forms that roll.
One of the problems with all of these earlier systems is that the support roll is generally subjected to significant temperature changes and extremes of temperature which create a variety of problems, even apart from the lubrication problem mentioned above, with respect to binding or seizing of the support roll or dimensional changes.
The variations in heating and cooling thus require a variety of expensive and frequently unreliable techniques for ensuring the original form of the support roll and to minimize the bending.